Transport and material handling systems have been used in many industrial operations for moving various articles through successive stages in a manufacturing process. For example, U.S. Pat. No. 3,490,575 issued to Thomas R. Herrmann on Jan. 20, 1970 describes a system for handling articles through a predetermined progression of stations or locations on a closed path utilizing a rotary transport system. However, in the transport device described in this patent, and in similar prior art devices involving the use of rotary turrets, the turrets are usually fitted with a single set of work stations such that during each revolution or cycle, only one function is performed on the turret. Therefore, in order to perform additional work functions, the workpiece must be transferred to a different turret for each succeeding function whenever a series of functions must be performed. Consequently, the resulting operation will not only become inefficient, but expensive as well.
U.S. Pat. No. 3,802,050 issued to George Verhoest on Apr. 9, 1974 also describes a rotary transfer apparatus designed especially for the manufacture of dry cells. This patent, however, is also typical of the prior art devices employing rotary turrets capable of performing a limited function on the workpieces on each turret.
Other patents of interest include U.S. Pat. Nos. 2,561,404; 2,874,701; 3,208,602; 3,461,535; 3,601,242 and 3,798,736.
So far as it is known, none of the devices disclosed in the prior art patents can be utilized efficiently in view of their inherent limitation as to their capabilities of carrying out a limited function on each turret.
Accordingly, it is an object of the present invention to provide an improved material handling system comprising turrets and cooperating transfer wheels in which more than one function can be performed continuously on each turret.
It is a further object of this invention to provide an efficient method and apparatus for the transport and assembly of workpieces continuously and at high rates of production.
It is also an object of the present invention to provide such apparatus and method which substantially reduces the size, number and thus the cost of machinery required in such operations and which requires less tooling, machinery and factory space.
The term "efficient" is intended to indicate that, by virtue of the unique design of the apparatus and the method of this invention, the various workpieces carried by the turrets are utilized to process work for a maximum interval during a single revolution of a given turret with a minimum of idle time at each work station. For example, the apparatus and the method of the present invention facilitates the location of at least two groups or sets of work stations on each of at least two turrets with the result that two different fabricating or processing steps are susceptible of performance in each turret virtually simultaneously as the turrets rotate and cooperate with associated transfer wheels.
The foregoing and other objects and features of the present invention will become more apparent from the following detailed description of the invention and the accompanying drawings.